文章目录

• 一、配置依赖

  plugins {id 'kotlin-kapt'
  }android {compileOptions {sourceCompatibility JavaVersion.VERSION_17targetCompatibility JavaVersion.VERSION_17}kotlinOptions {jvmTarget = '17'}
  }dependencies {implementation("androidx.room:room-runtime:2.4.2")kapt("androidx.room:room-compiler:2.4.2")
  }

• 二、标记实体类

  @Entity(tableName = "banner")
  data class Banner(val desc: String,@PrimaryKeyval id: Int,val imagePath: String,val isVisible: Int,val order: Int,val title: String,val type: Int,val url: String
  )

• 三、封装工具类

  object RoomUtil {@Volatileprivate var mDataBase: MyDataBase? = nullfun getInstance(context: Context): MyDataBase {if (mDataBase == null) {synchronized(this) {if (mDataBase == null) {mDataBase = Room.databaseBuilder(context, MyDataBase::class.java, "my_database").allowMainThreadQueries().build()}}}return mDataBase!!}@Database(entities = [Banner::class], version = 1)abstract class MyDataBase : RoomDatabase() {abstract fun bannerDao(): BannerDao}@Daointerface BannerDao {@Query("SELECT * FROM banner")fun getBanners(): List<Banner>@Query("SELECT * FROM banner WHERE id = :userId")fun getBannerById(userId: Int): Banner?@Insert(onConflict = OnConflictStrategy.REPLACE) //重复时则会替换fun insert(user: Banner)@Deletefun delete(user: Banner)@Updatefun update(user: Banner)}
  }

• 四、使用

  data.forEach {RoomUtil.getInstance(this@WelcomeActivity).bannerDao().insert(it)}val banner = RoomUtil.getInstance(this@WelcomeActivity).bannerDao().getBanners()[0]RoomUtil.getInstance(this@WelcomeActivity).bannerDao().delete(banner)
  RoomUtil.getInstance(this@WelcomeActivity).bannerDao().getBanners()
  RoomUtil.getInstance(this@WelcomeActivity).bannerDao().getBannerById(banner.id)